Precipitated calcium carbonate (PCC) pigments have found increasing application as fillers and as coating pigments in the manufacture of paper and paper board. This utility arises by virtue of PCC's excellent optical and physical properties when used for papermaking.
PCC is traditionally prepared by carbonating an aqueous calcium hydroxide slurry with a carbon dioxide gas to obtain calcium carbonate particles. The traditional process for the production of PCC is quite adequate for particles that do not require discreteness. However, there are problems with the traditional method for producing PCC where discreteness of the final particle is required.
When attempting to precipitate discrete PCC particles by using the traditional process that would naturally form clustered or agglomerated morphologies, it is very difficult to control process parameters so as to consistently produce discrete particles of calcium carbonate. Consequently, particles made according to the traditional process result in average particle size particles and specific surface area that are not very predictable with regard to control. The present invention resolves the problems of the prior art.
It is therefore an object of the present invention to provide a method for producing discrete calcium carbonate particles. Another object of the present invention is to provide a method for producing discrete calcium carbonate particles having a predictable average particle size and having a specific surface area. While another object of the present invention is to provide a reliable method for the preparation of discrete calcium carbonate particles. While a further object of the present invention is to produce discrete calcium carbonate particles having high calcium carbonate purity. While still a further object of the present invention is to produce discrete calcium carbonate products from lime sources of varying quality.
These and other objectives of the present invention will become more apparent as further provided in the related art and detailed description which follows.